How to display the entire value of a custom field with a check of these values?

Question

WordPress

There is a custom taxonomy Service and 6 services are nested in it.
On the page output through the loop these services.

$terms = get_field('service');
      if( $terms ): ?>
        
        <?php foreach( $terms as $term ): ?>
          <?php $r++; ?>
          <li class="cat-item cat-item-3"><a href="<?php echo get_term_link( $term ); ?>"><?php echo $term->name; ?></a></li>
        <?php endforeach; ?>

Only those services that are specified in the entry are displayed. And how to make it so that there would be a list of all services, and those that were available were marked (For example, if the service is not available, it is crossed out and there is a cross next to it, and the one that is available will have a tick next to it).

I tried to put a condition in the middle of the loop, but if there is no field, then nothing can be displayed.

Answer 1

And how is $terms stored, the key is the term ID there?